The applicant proposes to study for an eight-month period at the Institute for Child Health Research (ICHR) in Perth, Australia, examining medication use, particularly pseudoephedrine use, in pregnancy. Pseudoephedrine, a decongestant, is vasoconstrictive, and there is evidence suggesting that maternal use in early pregnancy increases risks of birth defects that are thought to arise from fetal vascular disruption. Dr. Werler has previously identified greater than 3-fold increased risks of two vascular disruption birth defects in relation to use of multiple-component pseudoephedrine products. No increase in risk was observed of either birth defect for single component pseudoephedrine. However, single component pseudoephedrine is less commonly taken in the U.S. and there were few exposed cases. Dr. Werler proposes to assess whether single component pseudoephedrine use increases risk of vascular disruption defects in Australia, where single component pseudoephedrine is more common. Dr. Werler's sponsor, Dr. Carol Bower, has recently completed a casecontrol study of birth defects, with standardized information collected on medication use. The proposed collaboration will involve Dr. Werler sharing her expertise in pharmacoepidemiology, Dr. Bower sharing her in-depth knowledge of the ICHR case-control study, and both Drs. Werler and Bower exchanging expertise in the classification of birth defects, particularly vascular disruption defects.